1. Field of the Invention
The present invention is generally directed toward biodegradable resin materials that have exhibit elastic properties that are uncharacteristic of many conventional biodegradable plastic materials. Particularly, the resin materials comprise a mixture of a starch component, a synthetic thermoplastic polymer resin, namely thermoplastic polyurethane, one or more plasticizing compounds, and a protein component, namely albumin.
2. Description of the Prior Art
The blending of starch with synthetic polymers in order to create polymeric resin compositions has been previously documented. Starch, an inexpensive filler material, has been blended with more expensive synthetic polymers, especially polyolefins, in order to reduce manufacturing costs and also to impart partial biodegradability to the resulting blend. U.S. Pat. Nos. 6,605,657 and 5,412,005 are exemplary of the art in this area.
However, the presence of starch has often had a negative impact on the physical and mechanical properties of the resulting mixture. For example, obtaining a finished article that sufficiently disintegrates and biodegrades, in that a sufficient portion of its carbon content is converted into CO2 under certain conditions, has proved elusive. Further, conventional biodegradable polymeric resins can be quite hard and brittle, and thus do not lend themselves to applications where a certain level of softness and elasticity are required.